1. Technical Field
The present disclosure relates to a power converter, and more particularly to a converter circuit with power factor correction, which raises the power converting efficiency and controls the input inrush current.
2. Description of Related Art
Recently, the switch power supply industry is growing rapidly, because it plays a most important role in the electronic apparatus. The switch power supply has the advantages of stability, simplicity, and efficiency when compared with the traditional power supply. When attention is paid to environmental protection and the energy saving, the trend about improvement of the alternating current (AC) isolated-switch power supply appears to be going to the topology of synchronous converting controlling in the secondary side and the power factor correction in the primary side.
The DC voltage is utilized in many electronic apparatuses. Since the supply terminal of Mains is the AC voltage, the electronic apparatus needs to perform AC-to-DC converting. For reducing the reactive power of the power system and current harmonic that interferes with the system, the electronic apparatus has been requested to have high power factor and low current harmonic, so the power factor corrector (PFC) is utilized universally. The PFC in common use is grouped in active type or passive type according to whether it includes an initiative switch wherein. Although each of the two types have advantages, there still exists the defect of bad current harmonic, low converting efficiency, big volume of the storage unit, or complicated way of control.
The power factor corrector including the bridge converter has become the main loss of high efficiency AC-DC power converter due to the voltage drop of the high forward-conduction voltage on the converting diode. In the traditional way, the converting diode is replaced by the Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). However, the high output voltage outputted by the traditional boost bridgeless PFC causes the rear stage DC-DC power converter to need to endure more high voltage stress and extra circuit to control the input inrush current, so the problem in administration and increased cost emerges. For resolving the above problem, the buck PFC circuit is further utilized. However, there still exists serious problems such as zero crossing distortion (ZCS) or dead zone, and also emerging is a total harmonic distortion and low power factor.